ixgbe: cleanup ixgbe_alloc_rx_buffers

This change re-orders alloc_rx_buffers to make better use of the packet
split enabled flag.  The new setup should require less branching in the
code since now we are down to fewer if statements since we either are
handling packet split or aren't.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ixgbe/ixgbe.h

@@ -472,7 +472,7 @@ extern void ixgbe_unmap_and_free_tx_resource(struct ixgbe_adapter *,
                                              struct ixgbe_tx_buffer *);
 extern void ixgbe_alloc_rx_buffers(struct ixgbe_adapter *adapter,
                                    struct ixgbe_ring *rx_ring,
-                                   int cleaned_count);
+				   u16 cleaned_count);
 extern void ixgbe_write_eitr(struct ixgbe_q_vector *);
 extern int ethtool_ioctl(struct ifreq *ifr);
 extern s32 ixgbe_reinit_fdir_tables_82599(struct ixgbe_hw *hw);

drivers/net/ixgbe/ixgbe_main.c

@@ -1010,63 +1010,70 @@ static inline void ixgbe_release_rx_desc(struct ixgbe_hw *hw,
  **/
 void ixgbe_alloc_rx_buffers(struct ixgbe_adapter *adapter,
 			    struct ixgbe_ring *rx_ring,
-			    int cleaned_count)
+			    u16 cleaned_count)
 {
-	struct net_device *netdev = adapter->netdev;
 	struct pci_dev *pdev = adapter->pdev;
 	union ixgbe_adv_rx_desc *rx_desc;
 	struct ixgbe_rx_buffer *bi;
-	unsigned int i;
-	unsigned int bufsz = rx_ring->rx_buf_len;
-
-	i = rx_ring->next_to_use;
-	bi = &rx_ring->rx_buffer_info[i];
+	struct sk_buff *skb;
+	u16 i = rx_ring->next_to_use;
 
 	while (cleaned_count--) {
 		rx_desc = IXGBE_RX_DESC_ADV(rx_ring, i);
+		bi = &rx_ring->rx_buffer_info[i];
+		skb = bi->skb;
 
-		if (!bi->page_dma &&
-		    (rx_ring->flags & IXGBE_RING_RX_PS_ENABLED)) {
-			if (!bi->page) {
-				bi->page = netdev_alloc_page(netdev);
-				if (!bi->page) {
-					adapter->alloc_rx_page_failed++;
-					goto no_buffers;
-				}
-				bi->page_offset = 0;
-			} else {
-				/* use a half page if we're re-using */
-				bi->page_offset ^= (PAGE_SIZE / 2);
-			}
-
-			bi->page_dma = dma_map_page(&pdev->dev, bi->page,
-						    bi->page_offset,
-						    (PAGE_SIZE / 2),
-						    DMA_FROM_DEVICE);
-		}
-
-		if (!bi->skb) {
-			struct sk_buff *skb = netdev_alloc_skb_ip_align(netdev,
-									bufsz);
-			bi->skb = skb;
-
+		if (!skb) {
+			skb = netdev_alloc_skb_ip_align(adapter->netdev,
+							rx_ring->rx_buf_len);
 			if (!skb) {
 				adapter->alloc_rx_buff_failed++;
 				goto no_buffers;
 			}
 			/* initialize queue mapping */
 			skb_record_rx_queue(skb, rx_ring->queue_index);
+			bi->skb = skb;
 		}
 
 		if (!bi->dma) {
 			bi->dma = dma_map_single(&pdev->dev,
-						 bi->skb->data,
+						 skb->data,
 						 rx_ring->rx_buf_len,
 						 DMA_FROM_DEVICE);
+			if (dma_mapping_error(&pdev->dev, bi->dma)) {
+				adapter->alloc_rx_buff_failed++;
+				bi->dma = 0;
+				goto no_buffers;
+			}
 		}
-		/* Refresh the desc even if buffer_addrs didn't change because
-		 * each write-back erases this info. */
+
 		if (rx_ring->flags & IXGBE_RING_RX_PS_ENABLED) {
+			if (!bi->page) {
+				bi->page = netdev_alloc_page(adapter->netdev);
+				if (!bi->page) {
+					adapter->alloc_rx_page_failed++;
+					goto no_buffers;
+				}
+			}
+
+			if (!bi->page_dma) {
+				/* use a half page if we're re-using */
+				bi->page_offset ^= PAGE_SIZE / 2;
+				bi->page_dma = dma_map_page(&pdev->dev,
+							    bi->page,
+							    bi->page_offset,
+							    PAGE_SIZE / 2,
+							    DMA_FROM_DEVICE);
+				if (dma_mapping_error(&pdev->dev,
+						      bi->page_dma)) {
+					adapter->alloc_rx_page_failed++;
+					bi->page_dma = 0;
+					goto no_buffers;
+				}
+			}
+
+			/* Refresh the desc even if buffer_addrs didn't change
+			 * because each write-back erases this info. */
 			rx_desc->read.pkt_addr = cpu_to_le64(bi->page_dma);
 			rx_desc->read.hdr_addr = cpu_to_le64(bi->dma);
 		} else {
@@ -1077,15 +1084,11 @@ void ixgbe_alloc_rx_buffers(struct ixgbe_adapter *adapter,
 		i++;
 		if (i == rx_ring->count)
 			i = 0;
-		bi = &rx_ring->rx_buffer_info[i];
 	}
 
 no_buffers:
 	if (rx_ring->next_to_use != i) {
 		rx_ring->next_to_use = i;
-		if (i-- == 0)
-			i = (rx_ring->count - 1);
-
 		ixgbe_release_rx_desc(&adapter->hw, rx_ring, i);
 	}
 }